.box{
  position: fixed;
  left: 0;
  top: 0;
  height: 100%;
  width: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 100;
  display: none;
  .mask{
    width: 40%;
    float: left;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
  }

  .body{
    width: 60%;
    float: right;
    height: 100%;
    background: white;
    z-index: 101;
    overflow: auto;
    padding: 15px;
  }
}

.show{
  display: block;
}